World leaders at the G8 summit in France have issued a joint call for the embattled Libyan leader Colonel Muammar Gaddafi to step down.

Russia, which has criticised Nato's campaign in Libya, said it agreed Col Gaddafi had lost all legitimacy.

In a communique issued at the end of a two-day summit, the G8 also criticised Syria's deadly crackdown on protesters.

The bloc's statement included plans for a $20bn (£12bn) package for Tunisia and Egypt over the next two years.

BBC world affairs correspondent Christian Fraser, at the summit in Deauville, says the communique by the leaders of the US, Russia, Japan, Germany, France, Italy, Canada and the UK has 25 pages and 93 sub-sections.

'Finish the job'

But the part that has attracted the greatest attention, he adds, is an agreement on all sides - including the Russians - that Col Gaddafi should step down.

In his comments at the end of the summit, French President Nicolas Sarkozy said the wording of the communique had been toughened overnight and fully endorsed by the Russians.

It says: "Gaddafi and the Libyan government have failed to fulfil their responsibility to protect the Libyan population and have lost all legitimacy. He has no future in a free, democratic Libya. He must go."

US President Barack Obama - after talks about Libya with the French president - said: "We are joined in resolve to finish the job."

Russian President Dmitry Medvedev told a news conference at the end of the gathering in Normandy that he was prepared to mediate Col Gaddafi's departure, but he said Libya should be preserved as a single state.

The communique was issued as Nato reported that government forces had laid landmines in the rebel-held western Libyan city of Misrata.

Nato intervened in Libya after the UN passed a resolution in March mandating the protection of civilians in the country, following the uprising against Col Gaddafi.

British Prime Minister David Cameron said the time was right to "ratchet up" pressure on the Libyan regime, as he confirmed that the UK would deploy Apache attack helicopters for the campaign.

But a statement issued by a group of former African presidents - including South Africa's Thabo Mbeki and Nigeria's Olusegun Obasanjo - expressed "grave concern" that there was still no sign of an end to Nato's campaign in Libya.

As Syrian government troops dispersed a new round of protests in Damascus, the G8 communique called on the regime to "stop using force and intimidation" against its people.

But while Russia was seen as having toughened its stance on Libya, Moscow insisted on softening the G8's wording on Syria.

It obliged its partners to drop a threat of UN Security Council sanctions in favour of more general warning of "further measures".